Auto translation (including bulk translation) functionality allows you to choose different translation drivers.
Next variants are available for you:
Yandex Translation Driver
For using Yandex: Free driver in bulk translation, you need to get your own API key and enter it on LangShop settings page.
How to get Yandex API key you can read here.
Google (Free) Translation Driver
It is a free multilingual machine translation service developed by Google, to translate text into other languages. There are no additional API keys required but it has worse translation quality than Google Professional (paid version of translation api).
Note: Google (Free) translation driver will work much slower (!) than other drivers.
Google (Professional) Translation Driver
It is a paid version of google translation API. It has better quality than previous translation drivers but required Paid API key.
To learn about pricing and how to get Google API key you can read here.